Evaluating mitochondrial uncoupling potentials of A7E and DNP in Saccharomyces cerevisiae : implications for human obesity

Obesity is one of the most prevalent maladies in the United States and is a major cause of preventable death. Weight loss supplements frequently claim uncoupling as a mechanism of action. Uncoupling agents could be used for weight loss because they disrupt mitochondrial metabolism thereby reducing adenosine triphosphate (ATP) yield. Consequently, metabolic efficiency diminishes increasing basal metabolic rate. 2,4-Dinitrophenol (DNP) successfully uncouples but was banned in 1938 because of a narrow window between efficacy and toxicity. PURPOSE: To measure the ability of a blend that reportedly contains 17-dihydroxy-delta-5-etiocholane-7-one and p-methylcarbonylethylphenol and other substances (A7E), a purported uncoupling agent, to interfere with oxidative phosphorylation in Saccharomyces cerevisiae as evidenced by lower ATP production. METHODS: Timed culture studies of S. cerevisiae were performed using two separate agents, A7E (a purported uncoupling agent) and DNP (a known uncoupling agent) at three doses (DNP: Low, Moderate, High; A7E: Low, Moderate, High ), and an ethanol-treated control to detect interference with mitochondrial coupling. Microbial staining was used to ascertain cell viability and any changes in cell densities. ATP production was estimated by measuring luminosity generated in culture supernatants using the ATP Bioluminescence Kit (Sigma St. Louis, MO.). RESULTS: Luminosity measurements estimating ATP production revealed statistically lower ATP in agent-treated supernatants than in control supernatants (p < 0.001) except for low dose A7E versus control (p > .05), suggesting that both A7E and DNP acted by a mechanism of uncoupling. Luminosity values were measured in relative luminosity units (RLU). Treatments with A7E at Low, Moderate, and High doses generated group mean luminosity values of 24,596, 16,038, and 6,969, respectively. Treatments with DNP at Low, Moderate, and High doses generated group mean luminosity values of 17,191, 11,901, 767 R